Method for crimping textile strands



Oct. 24, 1967 K, STANLEY 3,348,283

METHOD FOR CRIMPING TEXTILE STRANDS Filed March 4, 1964 2 Sheets-Sheet i ,4 5 C D A? 5 5 49 HEATING INTERMEDIATE COOLING ZONE ZONE ZONE 1 I I a w W X Y Z 6 :7 5 f8 2 0 o N T R o L L E R 6 3 INVENTOR. 0 63 3 EC BISOBEQT STA/VLF) 68 3 7Z6 k/cdw 2 Sheets-Sheet 2 R. K. STANLEY METHOD FOR CRIMPING TEXTILE STRANDS INVENTOR. P036797 K STA/VLF) BY ATTUf/VEYJ.

United States Patent 3,348,283 METHOD FQR CRIMPENG TEX'HLE STRANDS Robert K. Stanley, Media, Pa, assignor to Techniservice Corporation, Philadelphia, Pa., a corporation of Pennsylvania Fiied Mar. 4, 1964, Ser. No. 349,338 2 Claims. (Cl. 28--72) This invention relates to strand treatment, particularly crimping of a textile strand.

There are a number of well known methods, primarily mechanical. of modifying the regularity of surface or rectilinearity of configuration of textile strands, many of which contain one or more synthetic filaments usually somewhat thermoplastic and characterized by undue surface regularity and configurational rectilinearity. Of those methods a very prominent one is stulfer-crimping; in that the strand is forced, as by and between a pair of counterrotating nip rolls, into a confining region from which its escape is impeded temporarily, as by suitable impeding means, sufficiently to cause the strand entering the region to bend back and forth upon coming into forcible contact with the accumulation of strand already present therein. Another one of those methods is gear-c-rimping, in which the strand is passed between intermeshing but spaced gears or the like and thereby bent from side to side into a zigzag crimped configuration resembling somewhat the usually more random configuration resulting from stufier-crimping.

Heating of the strand preparatory to or during crimping is known, as is subsequent cooling thereof. However, such heating and cooling may be imperfectly accomplished or controlled so as to have undesirable consequences, at least on certain types of strand or on strands having certain chemical composition. If imperfectly crimped the strand may have undesirably non-uniform or unstable crimp configuration.

A primary object of the present invention is improvement in the configuration or stability (or both) of crimp in textile strands.

Another object is improved temperature control in crimping of textile strands.

A further object is improvement in stulfer-crimping of textile strands.

Other objects of this invention, together with means and methods for attaining the various objects, will be apparent from the following description and the accompanying diagrams.

FIG. 1 is a schematic representation, largely in block form, of strand treatment according to the present invention;

FIG. 2 is a schematic representation of stuffer-crirnping apparatus useful according to FIG. 1;

FIGS. 31:, 3b, and 3c are schematic representations of items of stuifer-crimping apparatus useful according to FIG. 2;

FIG. 4 is a front elevation of a stuifer-crimper such as shown schematically in FIG. 2;

FIG. 5 is a side elevation of the apparatus of FIG. 4;

FIG. 6 is a top plan of the apparatus shown in elevation in FIGS. 4 and 5;

FIG. 7 is a schematic representation of electrical circuitry and related components useful in apparatus according to FIG. 1; and

FIG. 8 is a schematic representation of other electrical circuitry and related components useful in apparatus according to FIG. 1.

In general, the objects of the present invention are accomplished, in treatment of a textile strand to crimp it. by preheating the strand to a temperature at which it is readily crimpable, before applying crimping stress, and maintaining the strand under essentially adiabatic 354,283 Patented Get. 24, 196'? Tee conditions throughout substantially the entire period of application of crimping stress, and then preferably cooling the strand.

FIG. 1 shows, schematically, strand 11 leaving wound package It) and passing through pigtail guide 12 and into the first of three blocks (14, 15, 16) from the last of which crimped strand 11 passes to wind up on package 19 driven by rotating roll 18 in surface contact therewith. Block 14 denotes a Heating Zone, which has initial and final boundaries A and B; block 15, an Intermediate Zone, with corresponding boundaries B and C; and block 16, a Cooling Zone, with boundarie C and D. Location W in the Heating Zone, locations X and Y in the Intermediate Zone, and location Z in the Cooling Zone are identified further below.

FIG. 2 shows, also schematically, strand 11 entering the nip of pair of rolls 21, and crimpe'd strand 11' leaving chamber 23, which is tapered at its opposite end or entrance 22 extending into the bight of the rolls. Location X is denoted as coincident with the roll axes, and location Y as at or near the end of the chamber, where the strand is released substantially from crimping stress applied to it in the chamber as the rolls feed additional strand 11 thereinto. Location Y coincides substantially, therefore, with the effective location of whatever temporarily impedes the strand from passing through and out of the chamber.

FIGS. 3a, 3b, and 30 show, also schematically, three conventional types of stutfer-crimping chambers, with particular reference to impeding elements for the strand in the chambers, shown in the order of their development: pivoted gate 25, reciprocating plunger 27, and unidirectionally moving or movable wheel 29 (which also comprehends belts, etc.) as the impeding elements in chambers 23. Each of these types of impeding means applies back-pressure to the strand seeking to escape from the chamber (or from that part thereof in which it is under crimping stress) as the rolls forcibly stuff more strand into the chamber through the entrance. Examples of the respective types of stulfer-crirnping elements may be found in US. Pats. 2,686,339, 2,734,229, and 3,027,619; hence, the omission of most details of their construction.

FIGS. 4, 5, and 6 show, in front elevation, side elevation, and top plan, respectively, stuifer crimper 30 readily adaptable for use with the mentioned representative types of impeding elements. Infeed guide 32 provides a path (shown in broken lines) for strand to the nip of a pair of rolls 31, 31' which are juxtaposed to one end of chamber 33, the front and back of which overlap the rolls to the nip in order to ensure entrance of the strand into the chamber. The chamber is supported by inverted U- frarne 35, in which axles 37, 37' for rolls 31, 31' are journaled. Gears 39, 39' at or near the opposite ends of the axles are in mesh with one another, and axle 37 carries also pulley 41. Motor 43 on the horizontal part of frame 35 has pulley 45 an shaft 44, and belt 46 passes about both pulleys 41 and 45.

A suitable impeding element such as one of those shown schematically in FIGS. 3a, 3b, and 3c and not shown in FIGS. 4, 5, and 6 will be used in the apparatus of the latter set of views. Thus, gate 25 may be pivoted to the top edge of chamber 33 and optionally weighted or spring-loaded; or plunger 27 may be inserted in the top end of the chamber, either fitting loosely therein to permit crimped strand to be withdrawn between the outside thereof and the inside wall of the chamber or with a central longitudinal bore to permit the strand to be withdrawn axially through the plunger; or one or more wheels, gears, belts or the like may be inserted through the wall of the chamber (upon provision of suitable openings therefor). Any other suitable impeding element may be 3 provided in the illustrated stuffer-crimper, or equivalent crimping means may be substituted.

As suggested by a comparison of FIGS. 1 and 2, each of which contains the reference characters X and Y, all or substantially all of the crimper itself should be located in Intermediate Zone 15. Heat is supplied in Heating Zone 14 to raise the temperature of the strand, and heat is removed in Cooling Zone 16 to lower the strand temperature, and these operations are controlled in appropriate manner, as indicated below. Intermediate Zone is maintained under essentially adiabatic conditions with the object of maintaining the temperature of the strand therein, and particularly during its pas-sage through the crimping means, essentially constant. The size of the Intermediate Zone, as measured by the time the strand is therein, should be great enough to permit or effect dimensional equilibrium in the strand, e.g., maximum shrink-age.

FIG. 7 shows, schematically, electrical circuitry and related components useful in region 51, which may be (or be part of) Heating Zone 14. Electrical potential E1 provides, via pair of leads 54, the input to electrical bridge 52, which may be a simple Wheatstone bridge (or a more complex type) provided with resistors (or other suitable impedance elements) R1, R2, R3, and R4 in its various arms: resistor R3 being a. thermistor having pair of leads 53 and being located in region 51 to sense the temperature thereof, and the other resistors being less susceptible to resistance change with variation in temperature (or being maintained at constant temperature). The bridge output is transmitted via pair of leads 55 to controller 56, which is supplied with electrical potential E2'via pair of leads 57 and which controls the temperature of region 51, in response to the bridge output, by means of'heating element RH located in that region an connected to the controller via leads 58.

Instead of being a resistor the heating element may be suitable radiant (or other) heating means and the leads thereto be suitable piping, the controller controlling the flow of heating fluid through the piping in. conventional manner as it can control the flow of heating electrical current. Further details of the controller and its connection into the circuit are omitted for simplicity, being obvious to persons having an understanding of the pertinent art. a I

FIG. 8 shows, also schematically, region 61, which may be (or be part of) Cooling Zone 16. It is provided with temperature-sensitive resistor orthermistor R5 located therein and having a pair of leads 63 to a bridge (not shown) by analogy to the similar elements of the immediately preceding view. Cooling element RC also located in region 61 has a pair of leads 68 to a controller (not shown),.the further analogy with the apparatus of FIG. 7 being apparent. The cooling element may be either a thermoelectric element or a refrigerating coil (in which instance leads 68 would be piping), for example. 1

Suitable insulation ofthe Heating, Intermediate, and Cooling Zones permits accurate control of the temperature thereof. The respective zones should be sufiiciently large, as compared with the rate of travel of the strand therethrough, to hold the strand for a long enough time to have the desired effect upon it' Temperature-sensing means may be provided at locations W, X, Y, Z,- as suggested above, or at other convenient locations to ensure accurate determination of temperature, together with temperature-controlling means as may be required for the desired temperature control. Insulation of the Intermediate Zone, which contains the crimping means, from the other two zones may suffice to ensure adiabatic conditions therein. However, it that does not sufiice to maintain the strand at essentially constant temperature therein, and especially while it is under crimping stress, one or more controllers (with heating or cooling elements, or both) may be employed as in the other two zones.

A strand being at least partially thermoplastic, as by having a thermoplastic component, when passed through the Heating Zone, should be heated to a temperature at which it readily accepts a crimp, usually at or in the vicinity of the softening temperature thereof. This varies, of course, for various strands and strand compositions but will be known to persons skilled in the art. Then the strand is crimped in the Intermediate Zone without significant change in temperature, and finally has its temperature lowered in the' Cooling Zone, whereupon the crimp is thereafter less readily reduced or removed.

Strands treated according to this invention are noted for improved crimp stability. Excellent results have been obtained upon strands composed wholly or in substantial part of nylon 6, and other thermoplastic strand compositions are also suitable. The illustration and description of apparatus herein is by way of example; modifications may be made therein while retaining all orsome of the advantages and benefits of this invention, which itself is defined as follows.

The claimed invention:

1. In treatment of an at least partially thermoplastic textile strand to crimp it, the improvement comprising preheating the strand to a temperature at which it is adapted to be stuifer-crimped, stufiing it into a confining zone through which its passage is impeded temporarily to crimp it, and maintaining it under essentially adiabatic conditions throughout substantially that entire zone.

2. In treatment of an at least partially thermoplastic textile strand to crimp it, the improvement comprising preheating the strand to a temperature at which it is adapted to be stuifer-crimped, stufling it into a confining zone through which its passage is impeded temporarily to crimp it, and maintaining it under essentially adiabatic conditions throughout substantially that entire zone, and cooling the strand below that temperature upon its exit from that zone.

. References Cited Mattingly 2872 ROBERT R. MACKEY, Primary Examiner. v I I 

1. IN TREATMENT OF AN AT LEAST PARTIALLY THERMOPLASTIC TEXTILE STAND TO CRIMP IT, THE IMPROVEMENT COMPRISING PREHEATING THE STRAND TO A TEMPERATURE AT WHICH IT IS ADAPTED TO BE STUFFER-CRIMPED, STUFFING IT INTO A CONFINING 